The number
A051031(n,r) of all r-regular (simple) graphs on n vertices.
| A005176 |
  |
A000012 |
A059841 |
A008483 |
A005638 |
A033301 |
A165626 |
A165627 |
A165628 |
| all r |
n\r |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
25 |
26 |
27 |
28 |
29 |
30 |
31 |
32 |
33 |
34 |
35 |
36 |
37 |
38 |
39 |
| 1 |
1 |
1 |
| 2 |
2 |
1 |
1 |
| 2 |
3 |
1 |
0 |
1 |
| 4 |
4 |
1 |
1 |
1 |
1 |
| 3 |
5 |
1 |
0 |
1 |
0 |
1 |
| 8 |
6 |
1 |
1 |
2 |
2 |
1 |
1 |
| 6 |
7 |
1 |
0 |
2 |
0 |
2 |
0 |
1 |
| 22 |
8 |
1 |
1 |
3 |
6 |
6 |
3 |
1 |
1 |
| 26 |
9 |
1 |
0 |
4 |
0 |
16 |
0 |
4 |
0 |
1 |
| 176 |
10 |
1 |
1 |
5 |
21 |
60 |
60 |
21 |
5 |
1 |
1 |
| 546 |
11 |
1 |
0 |
6 |
0 |
266 |
0 |
266 |
0 |
6 |
0 |
1 |
| 19002 |
12 |
1 |
1 |
9 |
94 |
1547 |
7849 |
7849 |
1547 |
94 |
9 |
1 |
1 |
| 389454 |
13 |
1 |
0 |
10 |
0 |
10786 |
0 |
367860 |
0 |
10786 |
0 |
10 |
0 |
1 |
| 50314870 |
14 |
1 |
1 |
13 |
540 |
88193 |
3459386 |
21609301 |
21609301 |
3459386 |
88193 |
540 |
13 |
1 |
1 |
| 2942198546 |
15 |
1 |
0 |
17 |
0 |
805579 |
0 |
1470293676 |
0 |
1470293676 |
0 |
805579 |
0 |
17 |
0 |
1 |
| 1698517037030 |
16 |
1 |
1 |
21 |
4207 |
8037796 |
2585136741 |
113314233813 |
733351105935 |
733351105935 |
113314233813 |
2585136741 |
8037796 |
4207 |
21 |
1 |
1 |
|   |
17 |
1 |
0 |
25 |
0 |
86223660 |
0 |
9799685588961 |
0 |
  |
0 |
9799685588961 |
0 |
86223660 |
0 |
25 |
0 |
1 |
|   |
18 |
1 |
1 |
33 |
42110 |
985883873 |
2807105258926 |
  |
  |
  |
  |
  |
  |
2807105258926 |
985883873 |
42110 |
33 |
1 |
1 |
|   |
19 |
1 |
0 |
39 |
0 |
11946592242 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
11946592242 |
0 |
39 |
0 |
1 |
|   |
20 |
1 |
1 |
49 |
516344 |
152808993767 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
152808993767 |
516344 |
49 |
1 |
1 |
|   |
21 |
1 |
0 |
60 |
0 |
2056701139136 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
2056701139136 |
0 |
60 |
0 |
1 |
|   |
22 |
1 |
1 |
73 |
7373924 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
7373924 |
73 |
1 |
1 |
|   |
23 |
1 |
0 |
88 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
88 |
0 |
1 |
|   |
24 |
1 |
1 |
110 |
118573592 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
118573592 |
110 |
1 |
1 |
|   |
25 |
1 |
0 |
130 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
130 |
0 |
1 |
|   |
26 |
1 |
1 |
158 |
2103205738 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
2103205738 |
158 |
1 |
1 |
|   |
27 |
1 |
0 |
191 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
191 |
0 |
1 |
|   |
28 |
1 |
1 |
230 |
40634185402 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
40634185402 |
230 |
1 |
1 |
|   |
29 |
1 |
0 |
273 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
273 |
0 |
1 |
|   |
30 |
1 |
1 |
331 |
847871397424 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
847871397424 |
331 |
1 |
1 |
|   |
31 |
1 |
0 |
391 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
391 |
0 |
1 |
|   |
32 |
1 |
1 |
468 |
18987149095005 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
18987149095005 |
468 |
1 |
1 |
|   |
33 |
1 |
0 |
556 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
556 |
0 |
1 |
|   |
34 |
1 |
1 |
660 |
454032821688754 |
  |
  |
  |
  |
  |
  |
  |
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  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
454032821688754 |
660 |
1 |
1 |
|   |
35 |
1 |
0 |
779 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
779 |
0 |
1 |
|   |
36 |
1 |
1 |
927 |
11544329612485981 |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
  |
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  |
  |
  |
  |
  |
11544329612485981 |
927 |
1 |
1 |
|   |
37 |
1 |
0 |
1087 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
1087 |
0 |
1 |
|   |
38 |
1 |
1 |
1284 |
310964453836198311 |
  |
  |
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  |
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  |
  |
  |
  |
  |
  |
310964453836198311 |
1284 |
1 |
1 |
|   |
39 |
1 |
0 |
1510 |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
  |
0 |
1510 |
0 |
1 |
|   |
40 |
1 |
1 |
1775 |
8845303172513781271 |
  |
  |
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  |
  |
  |
8845303172513781271 |
1775 |
1 |
1 |